Wave energy converter

ABSTRACT

An improved wave energy converter for use in offshore and deep-sea locations. The wave energy converter is adapted for secure attachment to the bottom of a body of water (e.g., the ocean floor), preferably beyond the breaker zone. The wave energy converter is selectively adjustable in length. A hydraulic power generation system is used to convert the energy present in the waves into hydraulic power that can be use to generate electricity and for other purposes, such as desalinization. The system may include a hydraulic piston assembly, a floatation device that is connected to the piston assembly, high and low pressure hydraulic reservoirs, and a hydraulically driven power generator. The floatation device moves upward in response to rising waves, and downward under the force of gravity in response to falling waves. The system utilizes this downward gravitational force to discharge fluid from the piston assembly, which in turn, drives the power generator. A control system is used to detect water conditions and to selectively adjust the length of the support structure and the fluid flow characteristics to dynamically optimize power generation based on changing water conditions.

FIELD OF THE INVENTION

This invention generally relates to a wave energy converter and moreparticularly, to a wave power generator that utilizes gravity as aprimary component in the generation of hydraulic energy, which can beused to generate electrical power, and that is selectively adjustable tooptimize power generation based upon water conditions.

BACKGROUND OF THE INVENTION

Waves contain a large amount of energy, which if converted intoelectricity, can help serve the world's increasing demands forelectrical power. Many attempts have been made to harness the energycontained in waves and convert that energy into electrical power. Theseattempts include shoreline type generators, which are constructed at ornear the shoreline, and offshore generators, which are constructedbeyond the breaker zone and/or in the deep sea. Shoreline generators aregenerally easier to construct, but produce less energy than offshoregenerators, which are able to capture the greater amount of energyavailable in deeper water.

Although offshore generators may provide a greater amount of energy,they suffer from some drawbacks. For instance, because of the increasedsize and power of offshore waves, the construction of these devices ismore difficult and complex. Furthermore, these devices are typicallyunable to dynamically adjust their operation to optimize powergeneration based upon water conditions. Additionally, these devicestypically rely only on the rising crests of waves and/or in theresulting changes in pressure to generate electricity, and do notutilize the force of gravity.

It would be desirable to provide an improved wave energy converter thatutilizes gravity as a primary component for generating hydraulic energyand is dynamically adjustable to optimize power generation based oncurrent water conditions. The hydraulic power can be used to generateelectricity and for other purposes, such as desalination.

SUMMARY OF THE INVENTION

The present invention provides an improved wave energy converter for usein offshore and deep-sea locations. The wave energy converter is adaptedfor secure attachment to the bottom of a body of water (e.g., the oceanfloor), preferably beyond the breaker zone. The wave energy converter isselectively adjustable in length. A hydraulic power generation system isused to convert the energy present in the waves into hydraulic powerthat can be use to generate electricity and for other purposes, such asdesalinization. The system may include a hydraulic piston assembly, afloatation device that is connected to the piston assembly, high and lowpressure hydraulic reservoirs, and a hydraulically driven powergenerator. The floatation device moves upward in response to risingwaves, and downward under the force of gravity in response to fallingwaves. The system utilizes this downward gravitational force todischarge fluid from the piston assembly, which in turn drives the powergenerator. A control system is used to detect water conditions and toselectively adjust the length of the support structure and the fluidflow characteristics to dynamically optimize power generation based onchanging water conditions. The hydraulic energy that is produced canalso be used to power other systems and devices, such as a desalinationsystem.

One advantage of the invention is that it provides a wave energyconverter that is designed to utilize the force of gravity as a primarycomponent of power generation.

Another advantage of the invention is that it provides a wave energyconverter that is selectively and dynamically adjustable to optimize thegeneration of power based on the current status of wave and/or swellactivity.

According to a first aspect of the present invention, a wave energyconverter is provided and includes a support structure fixed to a floorof a body of water; a piston assembly including a housing that forms achamber containing an amount of pressurized fluid and having a first endattached to the support structure and a second end, a piston that isslidably disposed within the chamber, and a piston rod that is attachedto the piston and that extends from the second end of the housing; abuoyant floatation device that is attached to the piston rod and that isadapted to cause the piston to move upward in the chamber in response toa rising wave, and to move downward by the force of gravity in responseto a falling wave, the downward motion and gravitational force beingeffective to discharge the pressurized fluid from the chamber; and ahydraulically driven power generator that receives the dischargedpressurized fluid from the chamber, and utilizes the pressurized fluidto generate electrical power or for other applications, such asdesalination.

According to a second aspect of the present invention, a wave powergenerator is provided and includes a support structure fixed to a floorof a body of water, the support structure including a pair oftelescoping members that are movable relative to each other, effectiveto adjust a length of the support structure; a hydraulic assembly thatis operatively coupled to the support structure and adapted to cause thetelescoping members to move relative to each other, thereby adjustingthe length of the support structure; a hydraulic piston assembly that isattached to the support structure and that contains an amount ofpressurized fluid; a buoyant floatation device that is attached to thehydraulic piston assembly and that is adapted to move upward in responseto a rising wave and downward under the force of gravity in response toa falling wave, the downward motion being effective to dischargepressurized fluid from the hydraulic piston assembly; a hydraulicallydriven power generator that receives the discharged pressurized fluidfrom the chamber, and utilizes the pressurized fluid to generateelectrical power; and a control system that is communicatively coupledto the hydraulic assembly and that is adapted to monitor waterconditions and to cause the hydraulic assembly to dynamically adjust thelength of the support structure based on the monitored water conditions.

According to a third aspect of the present invention, a method forconverting energy from waves formed in a body of water is provided. Themethod includes steps of: providing a floatation device that is adaptedto move upward in response to a rising wave and downward under the forceof gravity in response to a falling wave; and utilizing the downwardmotion and gravitational force of the floatation device to drive fluidthrough a hydraulically driven power generator, thereby generatingelectrical power. The floatation device may be attached to a hydraulicpiston assembly containing fluid, such that the downward motion of thefloatation device actuates the piston assembly, thereby driving thefluid through the hydraulically driven power generator. The pistonassembly may be supported at a certain height above a bottom of the bodyof water. The method may further include the steps of monitoring waterconditions; and selectively adjusting the certain height based upon themonitored water conditions; and/or controlling the flow of fluid throughthe hydraulically driven power generator based upon the monitored waterconditions.

These and other aspects, features, and advantages of the presentinvention will become apparent from a consideration of the followingspecification and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a wave power generator, according to thepresent invention.

FIG. 2 is a top view of an embodiment of the wave power generator,showing the general shape of the foundation.

FIG. 3 is a side view of one embodiment of a locking device for use withthe wave power generator shown in FIG. 1.

FIG. 4 is a side view of one embodiment of a pivot and damper assemblyfor connecting a piston to the platform of the generator shown in FIG.1.

FIG. 5 is a side view of one embodiment of a pivot and damper assemblyfor connecting a float to the piston assembly of the generator shown inFIG. 1.

FIG. 6 is a cross-sectional view of one embodiment of a float for usewith the generator shown in FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will now be described in detail with reference tothe drawings, which are provided as illustrative examples of theinvention so as to enable those skilled in the art to practice theinvention. Where certain elements of the present invention can bepartially or fully implemented using known components, only thoseportions of such known components that are necessary for anunderstanding of the present invention will be described, and detaileddescriptions of other portions of such known components will be omittedso as not to obscure the invention. Embodiments of the present inventionare illustrated in the Figures, like numerals being used to refer tolike and corresponding parts of various drawings.

Referring now to FIG. 1, there is shown one embodiment of a wave powergenerator 10 that is made in accordance with present invention and thatis adapted for use in offshore and deep-sea locations. Wave powergenerator 10 is adapted for secure attachment to the bottom or “floor”12 of a body of water, such as an ocean or sea. The wave power generator10 is effective to convert the energy present in the waves or swells 14into electrical power. More specifically, the embodiment shown in FIG. 1is used to generate hydraulic power, which in turn, runs an electricalpower generator. However, in other embodiments, the generated hydraulicpower can be used to run other systems or devices, such as adesalination system. It should be appreciated that a power generationsystem or facility may utilize several wave power generators 10 tocollectively generate power in a selected location.

As shown, wave power generator 10 includes a dynamically adjustablesupport structure 16, a power generation system 15 having a hydraulicpiston assembly 18, a floatation device 20, high and low pressurehydraulic reservoirs 22, 24, and a hydraulically driven power generator26, and a control system 28.

Support structure 16 is secured to the ocean floor 12 by use of afoundation 30. Foundation 30 preferably extends a substantial depthbelow the ocean floor 12 sufficient to hold generator 10 in a fixedposition. Foundation 30 may be formed from a conventional durable anddense material, such as reinforced concrete. FIG. 2 is a top view of thegenerator 10 and illustrates the shape of one embodiment of thefoundation 30. Particularly, in the FIG. 2 embodiment, the foundation 30is generally elliptical in shape and is positioned with its longitudinalaxis 110 substantially parallel to the direction of the wave swells 120.This type of shape and positioning will minimize bottom disturbance.However, in other embodiments, the foundation can be made designed to bewider in order to create wave height amplification in areas of lowerwave energy. As shown in FIG. 2, additional wave power generators 10 maybe grouped in the same general proximity and positioned in the samegeneral direction. In alternate embodiments, structure 16 may beanchored to other structures that are fixedly anchored to the oceanfloor, such as drill platforms, piers and other suitable, stablestructures. Support structure 16 includes a pair of generally elongated,telescoping members 32, 34. Telescoping members 32, 34 allow the overalllength (L) of the support structure 16 (which in this embodimentcorresponds to the overall height of the structure 16 above the oceanfloor 12) to be selectively adjusted to optimize the power generationprocess of the generator 10. In the preferred embodiment, member 34 isselectively moved relative to member 32 by use of hydraulic force, asdescribed below. However, in alternate embodiments, the length (L) ofthe support structure 16 may be adjusted in any other suitable manner.

Member 32 includes a generally solid lower portion 36, which is fixedlyattached to foundation 30, and a generally hollow upper portion 38,which slidably receives member 34. Upper portion 38 of member 32 formsan inner chamber 40 that may be filled with pressurized hydraulic fluid,in order to selectively and dynamically raise and lower member 34relative to member 32. Particularly, a conventional hydraulic assembly42 may be fluidly coupled to chamber 40 by way of one or more conduits44. Hydraulic assembly 42 may include one or more reservoirs andelectronically actuatable valves (not shown) that cooperate toselectively communicate pressurized hydraulic fluid to and from chamber40 in a known manner by way of conduit(s) 44. Hydraulic assembly 42operates under control of control system 28, as discussed more fully andcompletely below.

Member 34 may include one or more conventional seals 46 that aredisposed around the outer circumference of the lower end 48 of member34. Seals 46 engage the inner surface of member 32 and prevent hydraulicfluid from escaping from chamber 40. A platform 52 may be fixedlyattached to the upper end 50 of member 34. Platform 52 may be used tosecure various components of the generator 10, such as high and lowpressure fluid reservoirs 22, 24, power generator 26, and control system28.

FIG. 3 illustrates one embodiment of a support structure 16′ including aselectively actuatable locking mechanism 130. In this embodiment, member34′ includes several concave grooves 132 formed on one side of its outersurface. The locking mechanism 130 includes a locking bar 134 and aspring-loaded hydraulic actuator 136, which is fixedly attached tomember 36 and operates by receiving hydraulic pressure from assembly 42.Preferably, the locking mechanism is in a normally closed state (i.e.,it is in a fail safe locked position when no pressure is applied toactuator 136), and opens in response to receiving hydraulic pressure.When the mechanism 130 is locked, the bar 134 engages one of grooves132, thereby preventing the movement of member 34′ relative to member36. When the mechanism 130 is unlocked, bar 134 is clear of member 34′,thereby allowing the member to move freely in response to hydraulicpressure.

Hydraulic piston assembly 18 includes a generally cylindrical housing 54having an interior fluid-containing chamber 56, and a piston 62, whichis slidably contained within chamber 56 and which operatively divideschamber 56 into an upper or “charging” chamber 58 and a lower or highpressure chamber 60. A piston rod 64 is attached to and extends downwardfrom piston 62.

Housing 54 is preferably made from a relatively strong durable material,such as a metal material. Housing 54 includes a closed top end 74, whichis fixedly attached to the bottom side of platform 52 in a conventionalmanner. Housing 54 further includes a bottom end 76 having a centralaperture 78 through which piston rod 64 slidably moves. A seal 80 isdisposed within the aperture 78. Seal 80 sealingly engages the outersurface of piston rod 64, thereby preventing the escape of fluid fromchamber 56 through aperture 78. Housing 54 further includes ports 82,which allow chamber 56 to fluidly communicate with conduits 68, 70 and72.

Conduits 68, 70 and 72 allow pressurized fluid to flow in and out ofchamber 56. Conduit 68 fluidly couples the upper chamber 58 to the lowerchamber 60. Conduit 70 fluidly couples the lower chamber 60 to the highpressure reservoir 22. Conduit 72 fluidly couples the low pressurereservoir 24 to the upper chamber 58. Each of the conduits may includeconventional check and/or flow valves that are designed to control theflow of fluid throughout the system and to prevent backflow.

Piston 62 is generally cylindrical in shape and has a diameter that issubstantially identical to the diameter of the interior chamber 56.Piston 62 further includes one or more o-rings 86 that sealingly engagethe interior surface of housing portion 54 that defines chamber 56,thereby substantially preventing fluid from flowing “through” or aroundpiston 62. Therefore, when piston 62 moves within chamber 56 in thedirections of arrows 88 and 90, all fluid which is transferred betweenchambers 58 and 60 must flow through conduits 68, 70 and 72. Piston rod64 includes a bottom end 84, which is fixedly attached to floatationdevice 20 in a conventional manner, such that the upward and downwardmovement of floatation device 20 is effective to actuate the pistonassembly 18.

In some embodiments, the piston assembly may be pivotally connected tothe main platform and/or to the floatation device 20. FIG. 4 depicts oneembodiment where a top end 75 of a piston assembly 18′ is pivotallycoupled to a bottom portion 53 of platform 52, thereby allowing theassembly 18′ to move in the directions of arrows 142. This embodimentfurther includes a spring-loaded damper 140, which is coupled toplatform 52 and to the central area of piston housing 54. Damper 140 maybe a conventional preloaded shock absorber device, which is adapted topreposition piston 18′ and floatation device 20 in the direction of theoncoming waves, such that piston assembly 18′ forms an acute angle 144with platform 52 toward the oncoming waves. The damper 140 allows pistonassembly 18′ to pivot in a controlled manner as the wave passes throughthe generator 10. In this manner, the damper 140 and pivoting pistonassembly 18′ operate to optimize energy transfer between the wave andgenerator 10 during the upstroke.

FIG. 5 depicts one embodiment where a floatation device 20′ is pivotallyconnected to the bottom end 84 of piston rod 64, thereby allowing thefloat 20′ to pivot in the directions of arrows 152. This embodimentfurther includes a spring-loaded damper 150, which is coupled to float20′ and to a bracket which is fixedly attached to piston shaft 64.Damper 150 may be a conventional preloaded shock absorber device, whichis adapted to minimize the swing of the float to protect shock impactson the device and assembly. The damper 150 may also preposition thebottom surface of floatation device 20′ so that large percentage of thebottom surface area of the device contacts the oncoming waves. Thedamper 150 will allow float 20′ to pivot in a controlled manner as thewave passes through the generator 10. In this manner, the damper 150 andpivoting float 20′ operate to optimize energy transfer between the waveand generator 10 during the upstroke.

Floatation device 20 may be generally semi-spherical in shape.Floatation device 20 is made from a buoyant but relatively heavymaterial. Preferably, floatation device 20 is made as heavy as possiblewhile retaining buoyancy. The rounded or bottom surface 92 of thefloatation device 20 engages the surface of the water or waves 14.Floatation device 20 has a preferably large diameter “D”, which may beoptimized based on the wave shape and height. It should be appreciatedthat both float size and shape can be optimized by scientificexperimentation based on the types of wave fronts typically encountered.The relatively large, rounded surface 92 allows a rising wave front tolift floatation device 20 relatively easily. The relatively heavy weightof floatation device 20 provides a strong gravitational force that pullsfloatation device 20 downward and forces pressurized fluid out ofchamber 60 during a falling wave.

FIG. 6 illustrates one embodiment of a variable weight floatation device20″ for use with generator 10. Float 20″ is generally hollow with aninner chamber 150. Several substantially parallel baffles 154 whichextend across the chamber 150 and minimize fluid shifting with thechamber 150. The lower ends of the baffles 154 include apertures orvents 156 which allow water to be relatively evenly distributed withinchamber 150. The bottom of the float 20″ includes an electrically orhydraulically actuated valve 152, which allows water to be selectivelyadded to and removed from the float 20″. The float 20″ further includesa vent 158 on its top surface that allows for air to be released fromchamber 150 to balance the pressure within the float 20″ when water isremoved or added. In the preferred embodiment, valve 152 iscommunicatively coupled to a hydraulic or electrical power source (e.g.,hydraulic assembly 42 or controller 98), which controls the actuation ofthe valve 152. By opening the valve 152 when float 20″ is in contactwith water, water will fill the chamber 150, thereby increasing theweight of the float 20″ (e.g., when a heavier float is desirable incertain wave conditions). Furthermore, when the float 20″ is raised outof the water, the valve 152 may be opened to release water from thechamber 150, thereby reducing the weight of the float 20″ (e.g., when alighter float is desirable, such as when making a height adjustment insupport 16).

In one embodiment, wave power generator 10 may include several hydraulicpiston assemblies 18 and floats 20, which are collectively coupled toreservoirs 22 and 24 and cooperate to charge the high pressure reservoir22, thereby collectively driving generator 26.

High pressure reservoir 22 and low pressure reservoir 24 areconventional hydraulic reservoirs, which are adapted to selectivelyreceive, hold and discharge hydraulic fluid. High pressure reservoir 22is fluidly coupled to lower chamber 60 by way of conduit 70, and tohydraulic power generator 26 by way of conduit 94. Low pressurereservoir 24 is fluidly coupled to upper chamber 58 by way of conduit72, and to hydraulic power generator 26 by way of conduit 96. Reservoirs22, 24 may include conventional electronically controlled flow valves,which control the rate of receipt and/or discharge of hydraulic fluidto/from the reservoirs, such as discharge valve 95, which selectivelycontrols the rate of flow of pressurized hydraulic fluid from highpressure reservoir 22 to generator 26. Such valves may becommunicatively coupled to controller 98, and controlled in aconventional manner by use of control system 28.

Power generator 26 is a conventional hydraulically driven electricmachine. Power generator 26 includes one or more conventional turbines(not shown), which are adapted to rotate in response to receivingpressurized hydraulic fluid from reservoir 22. The rotating turbine(s)is used to generate electricity in a known and conventional manner. Forexample, the turbine(s) may be coupled to and/or form a portion of amagnetic rotor assembly having a plurality of poles (e.g., north andsouth permanent and/or soft magnetic members). The rotor may rotatewithin or near a conventional stator assembly to produce electricalpower. The electrical output of generator 26 may be selectivelycontrolled in a known manner (e.g., by use of one or more field coils,which may be communicatively coupled to control system 28), in order toprovide a relatively consistent output voltage or power over a range ofoperating speeds and temperatures. In alternate embodiments, the powergenerator 26 may be replaced with other devices that can be driven bypressurized fluid and/or rotary motion, such as a pump, desalinationsystem and/or other mechanical, electrical or electromechanical devices.

In the preferred embodiment, control system 28 includes a controller 98and a plurality of sensors 100. Controller 98 is communicatively coupledto sensors 100 and to hydraulic assembly 42. Control system 28 mayfurther include an antenna/receiver assembly 102 for receivingelectromagnetic transmissions, which may provide information forcontrolling the operation of wave power generator 10. In the preferredembodiment, controller 98 may comprise a conventionalmicroprocessor-based controller operating under stored program control.As discussed in greater detail below, controller 98 receives signalsgenerated by sensors 100 and antenna/receiver 102 and utilizes thereceived signals to determine the optimal fluid flow characteristics forthe power generation system 15 and an optimal length (L) for the supportstructure 16 in order to provide for optimal power generation. Basedupon these determinations, controller 98 may generate command signals toselectively activate the flow valves within power generation system 15(e.g., valve 95) and the hydraulic assembly 42 to cause supportstructure 16 to adjust to the optimal length (L). Controller 98 may alsobe adapted to detect when wave conditions are such that continuedoperation may damage the power generation system 15. Controller 98 maycause support structure 16 to rise so that piston assembly 18 andfloatation device 20 are not impacted by the waves.

Sensors 100 comprise conventional and commercially available sensors,which are adapted to sense wave and water level conditions. For example,sensors 100 may comprise one or more pressure sensors that are attachedto support structure 16 at some point below the water surface. Thepressure sensors may be adapted to sense changes in pressure based onthe water level (e.g., when the water level is high, the sensors willsense an increased pressure). Sensors 100 may alternatively comprise anarray of moisture sensors. The moisture sensors may be adapted to detectwhen locations along support structure 16 become submerged. In eithercase, the data provided by sensors 100 allows controller 98 to determinewater conditions such as tidal levels or conditions (e.g., average depthof water), wave/swell height (e.g., the distance from wave peak totrough), and wave frequency.

Antenna/receiver unit 102 comprises a conventional antenna 104 forreceiving electromagnetic signals and a receiver 106 for amplifyingand/or processing the signals, and communicating the signals tocontroller 98. The signals may include conventional weather broadcastsand marine advisories which may provide data describing weather, water,wave and tidal conditions. The data may be processed in a conventionalmanner by controller 98 and used to determine an optimal length (L) forstructure 16 and/or optimal fluid flow characteristics for the hydraulicassembly 15, based on expected water conditions.

In operation, the wave power generator 10 is preferably disposed in anoffshore location where ocean waves/swells carry substantially moreenergy. For instance, the wave power generator 10 may be operativelydisposed beyond the just beyond breaker zone and/or in the deep sea at arelatively high latitude location. However, it should be appreciatedthat the wave power generator 10 can also function and produce desirablelevels of electricity in other locations. As the flotation device 20rides an upward wave swell, fluid is exchanged with low resistancebetween the upper charging chamber 58 and the lower charging chamber 60through conduit 68. As the wave 14 begins to fall, the force of gravityacts on the relatively heavy floatation device 20, pulling the piston 62downward. The downward motion and gravitational force causes the piston66 to pressurize the fluid within chamber 60 and to displace thepressurized fluid into high pressure reservoir 22 by way of conduit 70.In one embodiment, the displacement pressure created by the downwardmoving piston 62 may be approximately 1,000-1,500 psi. This pressure maybe adjusted based on the size, weight and shapes of the components ofthe piston assembly 18 and floatation device 20. During the down stroke,substantially all of the fluid is displaced into the high pressurereservoir 22. Pressurized fluid is then discharged from reservoir 22into the hydraulically driven power generator 26, where it is channeledthrough one or more turbines. The resulting rotation of the turbine(s)is used to create electrical power, in the manner described above.Controller 98 may selectively control the discharge vale 95 to ensurethat fluid is discharged from the reservoir 22 to the power generator 26at a rate and pressure that allows the turbine to rotate continuouslybetween swells. After the fluid passes through generator 26, it iscommunicated to the low pressure reservoir 24 by way of conduit 96. Lowpressure reservoir 24 holds the charging fluid during the down strokeand allows for pressure bleed off.

Controller 98 may monitor sensors 100 and/or data from antenna/receiverunit 102 to determine the optimal amount of fluid pressure and/ordischarge rate to be provided to the generator 26. Controller 98 maycommunicate control signals to valve 95, effective to control the rateat which fluid is discharged from reservoir 22 to generator 26. Forexample, in relatively strong wave conditions (e.g., when sensors 100detect a relatively large wave peak to trough distance), controller 98and valve 95 may cooperatively cause a higher rate of fluid discharge tothe power generator 26, since the compression stroke of the pistonassembly 18 will be larger and provide a greater amount of displacedpressurized fluid. At relatively low wave conditions (e.g., when sensors100 detect a relatively small wave peak to trough distance), controller98 and valve 95 cooperatively may cause a lower rate of fuel dischargeto the power generator 26 in order to keep the turbine(s) within thepower generator 26 continuously rotating, since a lesser amount of fluidmay be displaced in the system. Additionally, the controller 98 maycontrol other valves within the hydraulic assembly 15 in order toselectively increase and decrease the ability of fluid to flowthroughout the assembly 15 based on water conditions to achieve certainelectrical output characteristics.

Controller 98 will also monitor sensors 100 and/or unit 102 for tidallevels, swell heights and wave frequency to determine an optimal length(L) for the support structure 16. Particularly, controller 98 monitorssensors 100 and/or data from unit 102 over predetermined periods of timeto determine the average water levels during wave peaks and troughs.Based on these average “high” and “low” water levels, controller 98 willcommunicate signals to hydraulic assembly 42, effective to adjust thelength (L) of support structure 16 so that the piston assembly 18 willhave a full range of stroke. For example, during a wave peak, the piston62 should preferably reach near the top of the cylinder 54, and during awave trough, the piston 62 should preferably reach near the bottom ofthe cylinder 54, such that substantially all fluid in the cylinder isdisplaced. These “preferred” positions, and consequently length (L), maychange based on wave height and frequency. Additionally, differentpositions may be chosen based on water conditions in to achievedifferent operational characteristics.

Controller 98 may also detect when water conditions are such thatcontinued operation may damage the power generation system 15 (e.g.,during heavy waves, storms or violent weather occurrences) by monitoringsensors 100 and/or weather data from unit 102. In these situations,controller 98 signals hydraulic assembly 42 to cause support structure16 to rise so that piston assembly 18 and floatation device 20 are at asafe height (e.g., not impacted by waves).

It should therefore be appreciated that the wave power generator 10provides an improved wave power generator that utilizes gravitationalforce (e.g., the substantial gravitational force produced by the fallingfloatation device 20) as a primary component in a power generationprocess. Furthermore, the control system 28 allows the operation of wavepower generator 10 to be selectively and dynamically adjusted tooptimize the power generation process based on the current status ofwave and/or swell activity.

It is understood that the invention is not limited by the exactconstruction or method illustrated and described above but that variouschanges and/or modifications may be made without departing from thespirit and/or the scope of Applicants' inventions.

1. A wave energy converter comprising: a support structure fixed to afloor of a body of water; a piston assembly including a housing thatforms a chamber containing an amount of pressurized fluid and having afirst end attached to the support structure and a second end, a pistonthat is slidably disposed within the chamber, and a piston rod that isattached to the piston and that extends from the second end of thehousing; a floatation device that is attached to the piston rod and thatis adapted to cause the piston to move upward in the chamber in responseto a rising wave, and to move downward by the force of gravity inresponse to a falling wave, the downward motion and gravitational forcebeing effective to discharge the pressurized fluid from the chamber; andat least one reservoir that is fluidly coupled to the piston assemblyand that receives and stores the pressurized fluid.
 2. The wave energyconverter of claim 1 further comprising: a hydraulically driven powergenerator that is fluidly coupled to the at least one reservoir and thatreceives and utilizes the pressurized fluid to generate electricalpower.
 3. The wave energy converter of claim 2 wherein the at least onereservoir comprises: a high pressure reservoir that is adapted toreceive fluid from the piston assembly, and to communicate the fluid tothe hydraulically driven power generator at a certain flow rate.
 4. Thewave energy converter of claim 3 wherein the high pressure reservoirincludes an adjustable valve that-is adapted to control the certain flowrate.
 5. The wave energy converter of claim 3 further comprising: a lowpressure reservoir that is fluidly coupled to the hydraulically drivenpower generator and to the piston assembly, the low pressure reservoirbeing adapted to receive fluid from the hydraulically driven powergenerator.
 6. The wave energy converter of claim 5 wherein the pistondivides the chamber into a charging chamber and a high pressure chamber,and wherein the piston assembly further comprises a conduit whichfluidly couples the charging chamber to the high pressure chamber,thereby allowing fluid to be communicated from the charging chamber tothe high pressure chamber as the piston moves upward in the chamber. 7.The wave energy converter of claim 5 wherein the support structureselectively adjustable in length.
 8. The wave energy converter of claim7 further comprising: a control system that is adapted to monitor waterconditions and to control operation of the wave energy converter basedupon the monitored water conditions.
 9. The wave energy converter ofclaim 8 wherein the control system is adapted to selectively adjust alength of the support structure based upon the monitored waterconditions.
 10. The wave energy converter of claim 9 wherein the controlsystem is adapted to control the flow of pressurized fluid through thehydraulically driven power generator based upon water conditions. 11.The wave energy converter of claim 8 wherein the control system isadapted to monitor water conditions by use of at least one sensor thatis attached to the support structure.
 12. The wave energy converter ofclaim 11 wherein the at least one sensor comprises a pressure sensor.13. The wave energy converter of claim 11 wherein the at least onesensor comprises a moisture sensor.
 14. The wave energy converter ofclaim 8 wherein the control system is adapted to monitor wave conditionsby use of an antenna/receiver unit that is adapted to receive whetherdata and provide the received weather data to the control system. 15.The wave energy converter of claim 9 wherein the control systemcomprises a hydraulic assembly adapted to selectively adjust the lengthof the support structure.
 16. The wave energy converter of claim 15wherein the support structure comprises first and second telescopingmembers that are selectively moved relative to one another by use of thehydraulic assembly.
 17. The wave energy converter of claim 1 wherein thefirst end of the piston assembly is pivotally attached to the supportstructure.
 18. The wave energy converter of claim 17 further comprisinga damper that is coupled to the piston assembly and to the supportstructure and that is effective to damp pivoting movement of the pistonassembly relative to the support structure.
 19. The wave energyconverter of claim 1 wherein the floatation device is pivotally attachedto the piston rod.
 20. The wave energy converter of claim 19 furthercomprising a damper that is coupled to the piston rod and to thefloatation device and that is effective to damp pivoting movement of thefloatation device relative to the piston rod.
 21. The wave energyconverter of claim 1 wherein the support structure includes a generallyelliptical foundation having a longitudinal axis positionedsubstantially parallel to the direction of wave fronts.
 22. A wave powergenerator comprising: a support structure fixed to a floor of a body ofwater, the support structure including a pair of telescoping membersthat are movable relative to each other, effective to adjust a length ofthe support structure; a hydraulic assembly that is operatively coupledto the support structure and adapted to cause the telescoping members tomove relative to one another, thereby adjusting the length of thesupport structure; a hydraulic piston assembly that is attached to thesupport structure and that contains an amount of pressurized fluid; afloatation device that is attached to the hydraulic piston assembly andthat is adapted to move upward in response to a rising wave and downwardunder the force of gravity in response to a falling wave, the downwardmotion being effective to discharge pressurized fluid from the hydraulicpiston assembly; a hydraulically driven power generator that receivesthe discharged pressurized fluid from the chamber, and utilizes thepressurized fluid to generate electrical power; and a control systemthat is communicatively coupled to the hydraulic assembly and that isadapted to monitor water conditions and to cause the hydraulic assemblyto dynamically adjust the length of the support structure based on themonitored water conditions.
 23. The wave power generator of claim 22further comprising: a high pressure reservoir that is fluidly coupled tothe piston assembly and to the hydraulically driven power generator, thehigh pressure reservoir being adapted to receive fluid from the pistonassembly, and to communicate the fluid to the hydraulically driven powergenerator at a certain flow rate.
 24. The wave power generator of claim23 wherein the high pressure reservoir includes an adjustable valve thatis communicatively coupled to the control system, wherein the controlsystem is further adapted to communicate signals to the valve, effectiveto control the flow of pressurized fluid through the hydraulicallydriven power generator based upon the monitored water conditions. 25.The wave power generator of claim 23 further comprising: a low pressurereservoir that is fluidly coupled to the hydraulically driven powergenerator and to the piston assembly, the low pressure reservoir beingadapted to receive fluid from the hydraulically driven power generator26. The wave power generator of claim 25 wherein the piston divides thechamber into a charging chamber and a high pressure chamber, and whereinthe piston assembly further comprises a conduit which fluidly couplesthe charging chamber to the high pressure chamber, thereby allowingfluid to be communicated from the charging chamber to the high pressurechamber as the piston moves upward in the chamber.
 27. The wave powergenerator of claim 22 wherein the control system is adapted to monitorwater conditions by use of at least one sensor that is attached to thesupport structure.
 28. The wave power generator of claim 27 wherein theat least one sensor comprises a pressure sensor.
 29. The wave powergenerator of claim 27 wherein the at least one sensor comprises amoisture sensor.
 30. The wave power generator of claim 27 wherein thecontrol system is adapted to monitor wave conditions by use of anantenna/receiver unit that is adapted to receive whether data andprovide the received weather data to the control system.
 31. A methodfor generating electrical power from waves in a body of water,comprising: providing a floatation device that is adapted to move upwardin response to a rising wave and downward under the force of gravity inresponse to a falling wave; and utilizing the downward motion andgravitational force of the floatation device to drive fluid through ahydraulically driven power generator, thereby generating electricalpower.
 32. The method of claim 31 further comprising: providing ahydraulic piston assembly containing fluid; supporting the hydraulicpiston assembly at a certain height above a bottom of the body of water;and attaching the floatation device to the piston assembly, such thatthe downward motion of the floatation device actuates the pistonassembly, thereby driving the fluid through the hydraulically drivenpower generator.
 33. The method of claim 32 further comprising:monitoring water conditions; and selectively adjusting the certainheight based upon the monitored water conditions.
 34. The method ofclaim 32 further comprising: monitoring water conditions; andcontrolling the flow of fluid through the hydraulically driven powergenerator based upon the monitored water conditions.